CONTEXT-FREE GROUPS AND THEIR STRUCTURE TREES
نویسندگان
چکیده
منابع مشابه
Context-Free Groups and their Structure Trees
Let Γ be a connected, locally finite graph of finite tree width and G be a group acting on it with finitely many orbits and finite node stabilizers. We provide an elementary and direct construction of a tree T on which G acts with finitely many orbits and finite vertex stabilizers. Moreover, the tree is defined directly in terms of the structure tree of optimally nested cuts of Γ. Once the tree...
متن کاملInverse Monoids, Trees, and Context-Free Languages
This paper is concerned with a study of inverse monoids presented by a set X subject to relations of the form ei = fi, i E I , where ei and fi are Dyck words, i.e. idempotents of the free inverse monoid on X. Some general results of Stephen are used to reduce the word problem for such a presentation to the membership problem for a certain subtree of the Cayley graph of the free group on X. In t...
متن کاملSemi-Groups Acting on Context-Free Graphs
Let ? be some context-free graph. We give suucient conditions on a semi-group of bisimulations H ensuring that the quotient Hn? is context-free. Using these suucient conditions we show that the quotient Aut(?)n? of ? by its full group of automorphisms is always context-free. We then give examples showing optimality (in some sense) of the above result.
متن کاملGroups with Context-free Co-word Problem
The class of co-context-free groups is studied. A co-context-free group is defined as one whose coword problem (the complement of its word problem) is context-free. This class is larger than the subclass of context-free groups, being closed under the taking of finite direct products, restricted standard wreath products with context-free top groups, and passing to finitely generated subgroups an...
متن کاملGroups with Context-Free Conjugacy Problems
The conjugacy problem and the inverse conjugacy problem of a finitely generated group are defined, from a language theoretic point of view, as sets of pairs of words. An automaton might be obliged to read the two input words synchronously, or could have the option to read asynchronously. Hence each class of languages gives rise to four classes of groups; groups whose (inverse) conjugacy problem...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: International Journal of Algebra and Computation
سال: 2013
ISSN: 0218-1967,1793-6500
DOI: 10.1142/s0218196713500124